R&S 4200 Series, Operating Manual

Page: 142 / 220

R&S XU 4200 Best Signal Selection
6166.5368.02.01 3.90
3.11 Best Signal Selection
0.
Best Signal Selection\Best Signal Selection "Radio".doc
This chapter This chapter provides information about the cabling, configuration and
conditions when using a pair of radios for best signal selection (BSS).
3.11.1 Introduction/Overview
Function description To optimize signal quality in difficult reception environments (shadowing,
etc.), two radios can be operated at different sites at the same frequency,
each with a separate antenna.
The radios automatically detect the one which receives the stronger audio
signal from the distant station, and this signal is connected through.
The "best signal" is determined by means of the two RSSI signals during
the first 200 ms of each radio message (PTT). The radio offering better
reception is then used during the entire radio message.
The radio which first switches the squelch on delivers a signal to the audio
line. After 200 ms the RSSI is sampled once and the radio with larger RSSI
value switches its signal to the audio line for the rest of the transmitted
audio burst. A new evaluation is done when the squelch opens again.
The following timing diagrams show the 2 possible cases (radio 1 with
stronger RSSI, radio 2 with stronger RSSI)
Fig. 3.85 Radio 1 has a stronger receive signal, no switchover audio
signal.